Sabot remover with helically arranged ridges



July 16. 1968 I. R. BARR 3,392,472

SABOT REMOVER WITH HELICALLY ARRANGED RIDGES Filed June 30, 1967 Flg z INVENTOR.

IRWIN R. BARR W w I: 3 W ATTORNEYS ABSTRACT OF THE DISCLOSURE A sabot remover for use on the forward end of a gun barrel consisting of a cylindrical member having an opening ,therethrough in axial alignment with the bore of the gun barrel. Helical ridges are provided within the opening and extending inwardly to a circumference less than the circumference of the barrel and are formed with an initial section at an angle of zero degrees, increasing, thereafter, along the length of the opening of the cylindrical member.

The invention relates to a sabot remover and more particularly to a sabot remover for stripping sabots from high velocity projectiles.

It is well known in the art to use a sabot to increase the velocity imparted to projectiles fired from guns. In the past, some of the prior methods utilized explosive charges to shatter the sabot, utilized sabots made of several pieces, or relied on air resistance to separate the sabot from the missile.

The present invention provides a sa'bot stripper of an improved configuration which is to be attached to the muzzle end of a gun barrel. In a previous Patent No. 2,811,901, issued Nov. 5, 1957, to Irwin A. Barr, a sabot stripper had been made which Was helical'ly grooved along its length, the helical groove being of constant helix angle, i.e. of constant cant angle. The ridges formed between the grooves had an internal diameter and circumference which was smaller than the external diameter of the sabot and the internal circumference of the gun barrel within which the sabot rode prior to entering the stripper, and consequently the sabot struck the inwardly protruding ridges of the stripper upon leaving the barrel. This abrupt striking of the sabot against the helical ridges tended to elfect shear cuts in the sabot corresponding to the ridges of the stripper. The helical angle of these ridges and grooves in combination with the forward motion of the sabot and projectile exerted a spin action on the sabot, which spin action was of material aid in subsequent centrifugal force removal of the sabot from the projectile after leaving the stripper. Thus, the sabot was not only physically damaged during passage through the stripper, but it also received a spin which was utilized to subsequently throw the physically damaged sabot fragments radially from the projectile.

This method of sabot removal caused the problems of short life of the stripper and inaccuracy of the projectile due to the abrupt striking of the sabot against the helical ridges of the remover.

In order to aid in smooth spin acceleration, and increase the accuracy of the projectile after separation from the sabot, the present invention is directed to an improved stripper or remover, in which the helical grooves and ridges of the stripper are formed with progressively in- Statcs PatentO 3,392,472 Patented July 16, 1968 2 creasing cant angles in the direction of travel of the projectile, i.e. in a direction extending away from the muzzle end of the gun barrel.

It is therefore an object of the present invention to provide a means for removing a sabot from a projectile by utilizing the velocity of the projectile and the centrifugal force developed by its axial rotation to fracture the sabot and separate it from the projectile.

Another object is the provision of a sabot stripper which provides superior accuracy to the projectile while providing increased wear life to the stripper.

The above objects as well as others together with the benefits and advantages of the invention will be apparent upon references to the detailed description set forth below, particularly when taken in conjunction with the drawing annexed hereto in which:

FIG. 1 is an isometric sectional view of the sabot remover of the present invention; and

FIG. 2 is a cross sectional view of a gun barrel equipped with the sabot remover shown in FIG. 1, showing a projectile carrying a sabot just prior to its emergence from the gun barrel.

As seen in the drawings, a sabot remover or stripper 10, adapted to be removably secured to the forward end of a gun barrel 12, see FIG. 2, is provided with interior threads 14 at the rearward end thereof which threads cooperate with threads 16 on said forward end of said gun barrel 12. The remover 10, which is of generally cylindrical shape, has a central opening 18 which is in axial alignment with the bore 20 of said gun barrel 12. A group of inwardly directed projections 22 forming helical grooves are formed with progressively increasing cant angles in the direction of travel of the projectile, i.e. in a direction extending away from the muzzle end of the gun barrel.

As seen in the drawings, an initial section of the stripper grooving is at a zero cant angle, with the degree of cant increasing thereafter along the length of the stripper. This structure permits the sabot to enter and be initially guided and cut by the stripper at zero spin and thereafter have a spin imparted thereto by the subsequently canted portion of the stripper projections. This is superior to the prior art where .there was an immediate exertion of a torsional spin force on the sabot at the same time that this sabot abruptly struck the stripper. This arrangement tends to give increased wear life to the stripper and increased accuracy to the projectile.

In operation, as seen in FIG. 2, a projectile 24 carrying a sabot 26 is fired from a gun equipped with the remover 10 on the forward end of its barrel 12. The sabot enters the remover and is initially guided and cut by the projection at zero spin and is thereafter caused to spin by the canted portion of the projections.

Due to the fact that the cant angle of the stripper increases toward its outer end, a constant acceleration of the sabot in spin is effected producing the lowest possible acceleration needed to achieve the required spin rate of the sabot in the short length of the stripper.

The remover or stripper may be adapted for use with guns of all sizes and projectiles and sabots of various types, and is particularly suited for use with plastic and other non-metallic sabots, and sabots made of the light weight metal.

It is to be understood that this invention is not restricted to the exact form depicted, and that modifications and changes may be made without departing from the scdpe of the invention.

I claim: 2. A sabot remover of the type described in claim '1,

1. A sabot remover adapted to fit on the forward end wherein said ridges are at an angle of zero degrees at that of a gun barrel comprising a cylin r c l member h v g portion of the remover adjacent said gun barrel and ina l passageway therethrough, sald' passageway belag creases in angle in a direction away from said gun barrel. in axial alignment with the bore of said gun barrel, said 5 passageway further having a plurality of ridges, helically References Cited th 'n fa th f th n t axfizriegield on e 1 ner sur ce ereo e arra gemen UNITED STATES PATENTS said ridges are formed with progressively increasing 2,81 1,901 I I/ 1957 Barr 8914 angles in a direction extending away from the forw ward end of said gun barrel. BENJAMIN A. BORCHELT, Primary Examiner. 

